The invention relates to the field of producing disposable lenses. Disposable lenses of this type consist of a flexible material and are produced by casting between two mould halves. A mould with suitably shaped mould halves must be available for each lens of a defined strength.
The known device which is used for that purpose comprises a large number of mould blocks, each of which is suitable for one pair of lenses. The mould blocks are conveyed along predetermined paths, past a number of processing stations. This known device is complicated and has a relatively low production rate.
The object of the invention is to provide a device which can be used to ensure a relatively high production rate and is less complicated and prone to faults.
This object is achieved by means of a device for producing disposable lenses by means of the steps of providing a concave mould and a convex mould for each lens, filling the concave mould with liquid starting material for the lens, and positioning the convex mould so as to enclose the said starting material, which device comprises a first carousel, a first station, which is arranged along the first carousel, for depositing the concave mould at a set position on the carousel, a second station for filling the deposited concave mould with starting material for a lens, a third station for depositing the convex mould so as to enclose the starting material, and a fourth station for removing the assembly comprising concave mould and convex mould with enclosed starting material from the first carousel.
In the device according to the invention, the moulds are situated on a carousel which provides a steady, smooth movement path.
The starting material for the lenses which has been deposited in the moulds is removed from this carousel by the fact that the fourth station for removing the assembly comprises an ejector member for moving the assembly off the carousel in the upward direction.
Furthermore, there is a second carousel, first transfer means for transferring each assembly from the first carousel to the second carousel, drying means, which are arranged along the second carousel, for drying the starting material, and means for removing each assembly from the second carousel. The drying means comprise a tunnel through which part of the circumference of the second carousel moves.
In connection with transferring the moulds and the starting material, the circumference of the second carousel partially extends above the circumference of the first carousel, in such a manner that at least one set position of the first carousel is aligned with respect to a set position on the second carousel, and an assembly can be transferred from one set position to the other set position by means of an ejector member.
Each set position on the second carousel contains a through-opening and a bearing member which is situated above this opening, which bearing member comprises at least two bearing halves which can be moved towards and away from one another, in such a manner that when the ejector member is moved upwards through the said opening the bearing halves are moved away from one another, and before the ejector member is moved downwards the bearing halves are moved towards one another in order to take an assembly off the ejector member.
Also, second transfer means are provided for transferring each assembly from the second carousel to a fifth station, which fifth station comprises removal means for removing the convex mould.
In connection with removing the lenses from the moulds, there is a third carousel and third transfer means for transferring an assembly comprising a concave mould and the starting material which has solidified in the drying means from the fifth station to the third carousel.
Means for loosening the solidified starting material with respect to the concave mould are situated along the third carousel; in particular, dropper means are provided for feeding demineralized water to the assembly comprising the solidified starting material and the concave mould.
Each carousel is provided with suction means for removing a mould.